✍ Scribed by Janet M. Kessler; Jonathan H. Reeder; Rahel Vac; Constance Yeung; John H. Nelson; James S. Frye; Nathaniel W. Alcock
No coin nor oath required. For personal study only.
The cadmíum (II) phosphine complexes (Et~3~P)~2~Cd~2~X~4~, (R~3~P)~2~CdX~2~ [R~3~P = Ph~3~,P, Bu~3~P, Et~3~P, 1‐phenyldibenzophosphole (DBP), and 1‐phenyl‐3,4,‐dimethylphosphole (DMPP)] and (Bu~3~P)~3~Cd~2~X~4~ (X = Cl, Br, I) have been prepared and their solution and solid state structures determined by a combination of elemental analyses, conductance, infrared and NMR spectroscopy. The structures of (Ph~3~P)~2~CdI~2~ (1) and (DBP)~2~CdI~2~ (2) have been determined from three‐dimensional X‐ray data collected by counter methods. Compound 1 crystallized in space group P2~1~,/a with a = 18.312 (9), b = 10.285 (5), c = 19.311 (9) Å, β = 115.53 (4)° and Z = 4. Compound 2 crystallized in space group P2~1~,/n with a = 12.698 (3), b = 15.302 (4), c = 17.477 (4) Å, β = 96.66 (2)° and Z = 4. The structures were refined by least‐squares methods with R~F~ = 0.041 and 0.048 for 4157 and 3393 unique reflections with I/σ(I) ⩾ 2.0 for 1 and 2, respectively. Both molecules deviate from ideal C~2~v symmetry and have very slightly different Cd‐I (1; 2.724 (2), 2.731 (2); 2; 2.718 (1), 2.721 (1) Å) and Cd‐P (1, 2.631 (2), 2.653 (2); 2; 2.616 (3), 2.603 (3) Å) bond distances. The Cd‐P bond distance differences are sufficient to give rise to a second order ABX CP/MAS ^31^P{^1^H} NMR spectrum for 1 but for 2 the phosphorus nuclei of the two DBP ligands are chemical shift equivalent. The CP/MAS ^113^Cd{^1^H} NMR spectra of both compounds 1 and 2 show apparent first order triplets. The (Bu~3~P)~3~Cd~2~X~4~ complexes are shown by variable temperature ^31^P{^1^H} NMR and conductance measurements to exist in solution as equilibrium mixtures of (Bu~3~P)~2~Cd~2~X~4~ and (Bu~3~P)~2~CdX~2~. CP/MAS ^31^P{^1^H} and ^113^Cd{^1^H} NMR spectra suggest that these compounds exist as doubly halide bridged (R~3~P)~2~Cd(μ‐X)~2~CdX~2~(R~3~P) species containing four‐ and five‐coordinate cadmium in the solid state. Equilibrium and activation thermodynamics for the ligand exchange processes of representative complexes have been determined from variable temperature ^31^P{^1^H} NMR spectra in CDCl~3~/CH~2~Cl~2~ (1:1) solutions.
📜 SIMILAR VOLUMES
The crystal structure of Cd 7 P 4 Cl 6 (I) has been redetermined and of Cd 4 P 2 Cl 3 (II) solved based on the single crystal X ray diffraction experiments. Crystal data: I, cubic space group Pa3, a ؍ 11.936(1) A s , z ؍ 4, and R ؍ 0.0226 for 398 independent reflections and 28 refined paramete